Solenoid valves are often used for regulating and controlling a volumetric flow, for example the fuel volumetric flow of a common-rail diesel injection system. During the operation of the solenoid valves, there is a risk that the temperature of the coil wire of the respective solenoid valve exceed a permissible maximum temperature. This may lead to a disturbance of the functioning of the solenoid valve and also to a destruction of the solenoid valve.
In order to avoid this, it is already known to measure a temperature value characterizing the coil temperature by means of a temperature sensor fitted on the housing of the coil of the solenoid valve.
However, one disadvantage of this procedure is that the temperature measured by a temperature sensor fitted on the housing of the solenoid valve does not correspond to the actual temperature of the coil wire. Instead, the temperature measures corresponds at most to an approximated value of the actual coil temperature.